A digital-to-analog converter (DAC) is an electronic circuit that receives an n-bit digital word and generates an analog output that is proportional to the received digital word. Digital codes are typically converted to analog voltages by assigning a voltage weight to each bit in the digital code and then summing the voltage weights of the entire code.
DACs can be designed for a wide range of applications, including general data acquisition applications and special applications, such as, but not limited to, video or graphic outputs, high definition video displays, ultra high-speed signal processing, and digital video recording.
The major factors that determine the performance quality of a DAC are resolution, speed, and linearity. Resolution refers to the smallest change in the output analog signal that is supported. The resolution determines the total number of digital codes, or quantization levels that will be recognized by a converter. The speed of a DAC is determined by the time it takes to perform the conversion process. Measurement accuracy is specified by a DAC's linearity. Integral linearity, which is also referred to as relative accuracy, is a measure of the linearity over the entire conversion range. It is often defined as the deviation from a straight line drawn between the endpoints and through zero (or offset value) of the conversion range. A DAC may use scrambling to increase linearity in the presence of non-linearities such as mismatches.
The accuracy of a DAC is critical in certain applications. The accuracy of a DAC may be increased by increasing the resolution of the DAC. Increasing the resolution often increases the cost and power requirements of the DAC.
Therefore, what are needed are systems and methods to reduce the impact of increasing the resolution of the DAC to improve DAC accuracy.
The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.